Pickup unit for stringed instruments



Dec. 7, 194.8. c. 1.. FENDER ETAL- 4 5 5 PICKUP UNIT FOR INSTRUMENTS Filed Sept. 26, 1944 25 if v (I i 2 9 ca 9 e Q i 2 d U i Patented Dec. 7, 1948 PICKUP'UN IT FOR STRINGE'D" INSTRUMENTS Glarence :LemEendemand Clayton .Orr Kauffmarn.

Eullertom C'alif.

Applicatiomseptember 26, 1944'; Serial Nor-55515818" 13x0laims: 1':

Our invention relat'esto =electrical pick -up units for: stringed instruments; andi among-the objects of our invention are:

First, toprovide anelectrical plcluup: unit for stringed? instruments; which produces amore natural tone: thanhasapreviously been-attained by-" electrical picki-up devices of this character.

Second, to provide anelectrical pick up' unit for stringed instruments-whereinthe string it self isthe only moving element in themagn'etic circuit; thusproducingwith great-fidelity cor.- responding. fluctuations or vibration: in; the: associatedzelectri'calicircuit;

Third}. to provide. an electrical pick-up Where'- in: all; soundin'gi-boardson sounding-boxes may baeliminatedi Fourth, to: provideran: electrical: pick-up which maybe associatedfW-ith any type of stringed 'im strument such amguitar; violin, pian'o and many othersz:

With the above and other objects inwiew; ref erence is directed. to: the: accompanying: drawings in which:

Fig}. 1 is av plan. view. of our pick-up unit as adapted. to usev in. conjunction w-itlraguitan:

Fig; 2 is. an enlargedzelevaticnal.view of the pick-.up-unit taken from the line. 2Z .of.Eig;.1.

Fig; 3 is axsimilarr elevationalzview: OIIthBf-DiCk up-unittaken: from. the: line. 3e-31'of-Eig; 1;.

Fig: 4 is an:enlargedtsectionalview oflthei-pickrup: unit takenv throrughi 4-4;- cfiFigz. l; the asso; ciatedpartsof. the guitar head'shownxfragmenttaril and :in-elevaticn;v

Fig, 5r-is a longitudinal sectionaltviewhof:a-mod; ified. form of our pick-up unit wherein. individ- .ualpick-up-coils are providedifor. each; string.

Our pick-up unit may be adapted fcnzusein anyof: the various "stringed instruments whether held in. the hands, such as'a guitar'or'violin; or whether larger in-size, such. as abass'viol... Also, our device may be employed irrespective of the number. of. strings contained. in themusicaliinstrument, that is, itanaybeused for aminstriuiment containing only a. few-strings, such as. a

guitar or violin, or for an-w instrument; contain:-

ing many strings, such. asa piano .on'harp.

For. convenienceof illustration; ourspickx-upmnit is shown asadapted'to a guitar. In placeiofa the usual sound-box, there is; provided: a: headmemher I which isfor the most part: solidv and con:- veniently shaped. It may be much smaller -than the conventional.- guitars sound-box. A. fretted neck-.2 similar. inv size and shape to: the conventional guitar, extends-:from -the bodyl andtenminates. in .a. conventional guitar. head- 3z-having 2 keys hwhichzserve :toadjust: the tension .Ofl'StGBl guitar strings 5.

AL portion: of; the top and: the extended .end. of the body: Ii's corverediby'a-plate formed oflsheet material preferably metal... At the right: angular juncture of the topsand end portions oftrthez-plate 6; thereais. formedLa' series of' V.-holes"|.'which receive. and secure. the extremitiesiofithestrings fi.

Our pick-up: unit. designatedzgenerally-i by; Ll, comprises. a..bottompolez member I21 andz'a top poleamember: I34; These area'chanrreL-shapedin cross-section, forming confronting: fonward flanges l4 and I5 respectively, and: rearward flanges; l6 and:- IT: respectively; Thee extremities anther. bottom anditop pole; members are. spaced by. magnets. I81. Thesermagnets may; bet-permanent: magnetsror-electromagnetsh In; the latter case. they. are. connectedrto. 3;; suitable source/t. of direct current. Screws; I9 secure: the assembly comprisingzthepole plates andmagnets together. The: pairs or: forward. and reanward-fiangesdefine gaps through; which: are: threaded. the: strips: 5. The: lower rearwarch flange I'T mayriorm a: bridge for: supporting; the-s strings 5;. and slightly notched toretainthesstrings. implace:

Theforward; flanges; It: and; I5; are. provided Withqa series ofjoppcsed' notches:2ll locatedgbee tween the strings-so' as' to. form: tooth-like. pole elements 2 I having-"parallel extremitiesonzvopposite sides ofeachxstring.

Between the bottom; and top" pole: members; and the magnets I8 is placed a pickeupcoilrZZ which may, embrace" all of thestringa The'upper. and lower. portions of the. Dick-up; coil may be. maintainedinspaced relation: by, spacers. 23 located bet-ween. the strings The pick-up unit is suitably mounted on: the plate 6 preferably withan insulation padthere.- between. Theplatefim'ay. be-flat as shown, or raised or depressed. atits; portion supporting the pick-up-unit. in order to. place? the strings. 5 at theproper" height,. or the; thickness: of the; insu- 1ation=padn24= may; be chosen toprovide: the: desired stringspacing.

Inzplace of the single pick-up coil 2-2rthe-stri'ngs 5: may be. surroundedbyindividual? pickeup" coils 25 as shown in Fig. 5;- In this case,,the indivividual pick-up coils. are-held-xin place. by nonmagnetic. holdenbars Z6" placed above and, below therpick-up coils;

The body I- of thezmusical instrument: may be providediwith-cavitiesto-accommodate a..volumecontrol anda: tone-control having diaisZI andt2 8 exposed through: SlOISilnr-thfi plate: 6. AcablerZS leading to asuitableamplifier: (not'shownlexthe individual pick-up coils 25. It is, of course,

essential that the strings 5 be formed at least in part, of magnetic material such as steel.

It should be observed that by reason of the fact that the strings rest on the rearward flange or pole piece ll and utilize this flange as a bridge, the fundamental and all of the harmonious vibrations of each string share a common node point located at the bridge. It has been found that this arrangement substantially increases the sensitivity of the instrument to all of the harmonic as Well as the fundamental notes produced by each string.

Also, it should be observed that the pole pieces formed by flanges it and it have like polarity,

which polarit is opposite to the polarity of the flanges or pole pieces l5 and I1; that is, if the pole pieces associated with the upper channel I3 are north, the pole pieces associated with the lower channel l2 will be south.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

We claim.

1. A pick-up device for stringed musical instruments, comprising a pair of U-shaped pole I.

pieces disposed with their leg portions confronting but spaced from each other and forming pole tips; a magnetic musical string extending longitudinally between said pole tips and forming an armature, said string being in physical contact with one of said pole tips to establish a common node point for all oscillations of said musical string; magnet means connecting said pole pieces to complete a magnetic circuit through said pole pieces and said musical string armature in which the polarity of the tips of each pole piece is the same but opposed to the polarity of the tips of the other pole piece; and a pick-up coil positioned in the magnetic field established by said magnetic circuit and influenced by variations in said magnetic field caused by movement of said musical string armature.

2. A pick-up device for stringed musical instruments, comprising: a pair of U-shaped pole pieces disposed with their leg portions confronting but spaced from each other and forming pole tips; a magnetic musical string disposed between said pole tips and forming an armature; a pair of magnetic blocks connecting said pole pieces at their extremities to complete a magnetic circuit through said pole pieces and said musical string armature in which both tips of each pole piece have the same polarity, but opposite polarity from the corresponding pole tips of the other pole piece; and an electric pick-up coil surrounding said musical string armature, and shielded by said magnet blocks and pole pieces. a

3. A construction as set forth in claim 2, wherein one of said pole tips is engaged by said musical string armature to form a bridge therefor; and wherein the pair of pole tips spaced along said musical string armature from said bridge forming pole tips are disposed clear of the lateral travel of said armature when said musical string armature is vibrated.

4. A pick-up device for stringed instruments, comprising: a series of tuned magnetic musical strings; a pair of channel-shaped pole pieces adapted to be disposed on opposite sides of said strings with their flange portions in confronting relation and forming sets of pole tips, the portions of said strings between said sets of pole tips forming armatures; magnet means connecting said pole pieces to form magnetic circuits through said pole tips and their respective musical string armatures the polarity of the tips of each pole piece being similar to each other but opposite from the corresponding tips of the other pole piece; and pick-up coil means disposed in said magnetic circuits and electrically influenced by Vibrations of said musical string armatures.

5. A construction as set forth in claim 4, wherein one set of said pole tips is serrated to form paired individual pole elements for each of said musical string armatures, and wherein one of the remaining pole tips is engaged by all of said musical string armatures to form a bridge therefor.

6. A pick-up device for stringed musical instruments, comprising: a musical string formed of magnetic material; a pair of confronting magnetic channel elements on opposite sides of and traversing said string to form pairs of pole pieces axially displaced relative to said string whereby the portion of string embraced between said pole pieces forms an armature; a magnet means for energizing said channel elements whereby the pole pieces of each channel element have identical polarity but opposite from the polarity of the other channel element; one of said pole pieces forming a bridge engaged by said string whereby all oscillations of said string have a common node point at said bridge; and an electric pick-up means disposed in the magnetic field formed by said magnetic channel elements and armature.

7. A pick-up device for stringed musical instruments, comprising: a series of musical strings formed of magnetic material arranged side by side; a channel-shaped magnetic structure forming opposed pairs of pole pieces traversing said strings and displaced from each other axially along said strings whereby the embraced portions of said strings form armatures; one of said pole pieces forming a bridge for said strings whereby all oscillations of said strings have node points at said bridge, the other pair of pole pieces being serrated with their projecting portions in substantial registry with the several strings but spaced therefrom; and a pick-up means in the magnetic field established by said magnet structure and armatures.

8. A pick-up device for stringed musical instruments as set forth in claim '7 wherein said pick-up means is a single pick-up coil embracing the armature portions of all of said strings.

9. A pick-up device fOr stringed musical instruments as set forth in claim 7 wherein said pick-up means comprises individual pick-up coils surrounding the armature portions of each string.

10. A pick-up device for stringed musical instruments, comprising: a series of musical strings formed of magnetic material arranged side by side; a pair of opposed channel-shaped magnet structures of opposite polarity each forming pole pieces of like polarity traversing said strings and displaced from each other axially along said strings whereby the embraced portions of said strings form armatures; the pole pieces of said magnet structures confronting each other, one

pole piece forming a bridge for said strings to establish common node points for the vibrations produced therein, and the confronting pair of pole pieces spaced therefrom being serrated with their projecting portions in registry to each other and said strings but spaced therefrom; and a pick-up means in the magnetic field established by said magnet structures and the armature portions of said strings.

11. A pick-up device for stringed musical instruments as set forth in claim 10 wherein said pick-up means is a single pick-up coil embracing the armature portions of all of said strings.

12. A pick-up device for stringed musical instruments as set forth in claim 10 wherein said pick-up means comprises individual pick-up coils surrounding the armature portions of each string.

13. A pick-up device for stringed instruments, involving: A pair of channel shaped pole pieces disposed with their flanges in confronting relation to define air gaps; a pair of magnets at the extremities of said pole pieces so arranged that the pole pieces have opposing polarity; a plurality of magnetic musical strings extending between said pole pieces, one of the flanges of said pole pieces being engaged by said strings and forming a bridge therefor, whereby each string has a node point for all mechanical oscillations thereof originating at said bridge; and an electric pick-up means within the space defined by said magnets and pole pieces.

CLARENCE LEO FENDER.

CLAYTON ORR KAUFFMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

